Integrated semiconductor Darlington pair construction - has input zero gain transistor and has transistor bases connected to surface layers by heavily doped zones

摘要

A Darlington pair amplifier (100) consists of two transistors in a monolithic planar structure. Switching speed is increased by use of a zero gain input transistor without increasing the size or complexity of the amplifier. The areas of the epitaxial layer which make up the transistor bases are connected to the surface layers by heavily doped zones, the doping type being the same as that of the bases. The emitter layers, also heavily doped (up to 1018 atoms/cm3), extend in the superficial layer. The depth, doping and profile of the doping are almost identical to that of a power transistor. The connection layer to the surface conductors is taken between the areas occupied by the transistors.